Buried-heterostructure lasers are more difficult to fabricate than weakly index guided or gain guided lasers. However, these strongly index guided structures are most suitable for a source of lightwave transmission systems. But, for conventional etched mesa buried heterostructure lasers, the regrowth of InP blocking layer is difficult and irreproducible. So, there are inevitable leakage currents flowing outside the active region resulting poor performance. To eliminate these problems, we used a planar buried heterostructure. As a results, the average threshold current was 28mA and the differential quantum efficiency was about 20% per facet for GaInAsP/InP PBH-LD. The initial forward leakage current was not exceeding and the reverse voltage for was -3V~-5V, these are improved figure of 1mA~10mA and -1V~-3V for EMBH laser diode. The chip modulation bandwidth was more than 2.4GHz for .

The stability and the electronic structure of .P-based superlattices are examined through self-consistent ab initio pseudopotential calculations. A chalcopyrite-like structure is found to be the lowest energy state over (001) and (111) monolayer superlattices (MLS). Our calculations indicate that all the ordered structures in bulk form are unstable against phase segregation into binary constituents at T = 0 while for epitaxial growth, the chalcopyrite phase is stabilized. The fundamental band gaps of the ordered structures are found to be direct and smaller than that of disordered alloys. The lowering of the band gap is explainable by band folding and pushing effects. We find the reduction of the band gap to be largest for the (111) MLS.

We fabricated very high. speed PIN Photodiode module for the application of high speed optical receiver. OMVPE was used for the growth of InP layer on InGaAs absorption layer. The structure was the combination of mesa and planartype. Fabrication procedure was more complicated than simple mesa or simple planar type structure because we used semiinsulating InP substrate in order to reduce stray capacitance. The results at-5V were as follows : dark current was less than 1nA, capacitance was 0.55pF, and cutoff frequency was above 3GHz, and rise and fall time was about 100ps.

has a very wide range of applications in optoelectronic devices especially for optical communications because has the bandgap of the lowest dispersion () and the lowest loss ( ) of the optical fiber by changing the composition. The quality of epitaxial layer is believed to have a significant effect on the performance of device. The OMVPE growth conditions for the latticematched /InP were investigated. Effects of growth conditions such as V/III ratio, growth temperature, and Ga source material on the electrical and optical properties were studied. The composition, electrical and optical properities of were characterized using double crystal X-ray diffractometer (DCD), photoluminescence (PL), XPS(ESCA) and Hall measurement.

Heavily unintentionally doped n-type InGaP wa grown by LPE technique. Temperature and excitation power dependence of PL measurements were carried out to investigate the first observed 2.107 eV PL peak in P. Also the unintentionally doped major impurity was found to be sulfur through XRF technique.